CALCIUM-PHOSPHATE SATURATION LEVELS IN ULTRAFILTERED SERUM
CALCIUM-PHOSPHATE SATURATION LEVELS IN ULTRAFILTERED SERUM
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DOI：
10.1007/bf02555708
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发表时间：
1987-02-01
影响因子：
4.2
通讯作者：
BROWN, WE
中科院分区：
文献类型：
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作者：
EIDELMAN, N;CHOW, LC;BROWN, WE
钙化发生在动脉斑块和其他病理性沉积物是重要的健康问题，这些沉积物的性质及其形成机制值得研究。用未稀释的超滤人血清（u.f.s.）在37度。通过持续搅拌和定期取出样品进行钙和磷酸盐分析以及pH值测量。溶解度测量在有和没有5.5%CO2气氛（CO2的生理分压）的情况下进行。本文研究了结晶良好的磷酸二钙（DCPD）、磷酸八钙（OCP）和羟基磷灰石（OHAp）在u.f.s.在每种情况下，从钙和磷酸盐浓度和pH计算，以与其已知的溶解度产品进行比较。以这种方式，结晶良好的磷酸钙用作基准溶解度标准，从而最小化由于钙和磷酸根离子通过u.f.s.选民。低于5.5%，CO2天然u.f.s.发现相对于DCPD基本上不饱和，相对于OCP略微过饱和，并且相对于OHAp高度过饱和。DCPD饱和u.f.s.中DCPD的离子活度积为2.4倍。10-7，以及OCP饱和u.f.s.中OCP的离子活度积。是4倍。10-49，略高于它们的溶度积（Ksp（DCPD）= 2.3 × 10 - 49）。10-7，Ksp（OCP）= 2.5 ×10-49）。DCPD和OCP的离子活度积以u.f.s.在CO2下的实验表明，钙和磷酸盐络合剂（除碳酸氢盐外）的浓度相当低。ufs即使在平衡2个月后，相对于OHAp仍保持过饱和。这归因于u.f.s.中晶体生长抑制剂的存在。
Calcifications occurring in arteriosclerotic plaque and other pathological deposits are important health concerns, and the nature of these deposits and their mechanisms of formation warrant investigation. Crystals of the relevant calcium phosphates were equilibrated with the undiluted ultrafiltered human serum (u.f.s.) at 37.degree. C by constant stirring and periodically removing samples for calcium and phosphate analysis and for pH measurement. The solubility measurements were carried out both with and without a 5.5% CO2 atmosphere, the physiological partial pressure of CO2. The apparent ion activity products of well-crystallized dicalcium phosphate dihydrate (DCPD), octacalcium phosphate (OCP), and hydroxyapatite (OHAp) equilibrated in u.f.s. were calculated from the calcium and phosphate concentrations and pH in each case for comparison with their known solubility products. In this way the well-crystallized calcium phosphates serve as fiducial solubility standards, thereby minimizing errors due to complexing of calcium and phosphate ions by u.f.s. constituents. Under 5.5%, CO2 native u.f.s. was found to be substantially undersaturated with respect to DCPD, slightly supersaturated with respect to OCP, and highly supersaturated with respect to OHAp. The ion activity product of DCPD in DCPD-saturated u.f.s. was 2.4 .times. 10-7, and the ion activity product of OCP in OCP-saturated u.f.s. was 4 .times. 10-49, slightly above their solubility products (Ksp(DCPD) = 2.3 .times. 10-7, Ksp(OCP) = 2.5 .times. 10-49). The ion activity products of DCPD and OCP in u.f.s. under CO2 indicate that the concentrations of calcium and phosphate complexing agents (except bicarbonte) are quite low. The u.f.s. remained supersaturated with respect to OHAp even after 2 months of equilibration. This is attributed to the presence of crystal growth inhibitors in u.f.s.